“Scentsor”: A Whole-Cell Yeast Biosensor with an Olfactory Reporter for Low-Cost and Equipment-Free Detection of Pharmaceuticals

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>Portable and inexpensive analytical tools are required to monitor pharmaceutical quality in technology limited settings including low- and middle-income countries (LMICs). Whole cell yeast biosensors have the potential to help meet this need. However, most of the read-outs for yeast biosensors require expensive equipment or reagents. To overcome this challenge, we have designed a yeast biosensor that produces a unique scent as a readout. This inducible scent biosensor, or “scentsor,” does not require the user to administer additional reagents for reporter development and utilizes only the user’s nose to be “read.” In this manuscript, we describe a scentsor that is responsive to the hormone estradiol (E2). The best estimate threshold (BET) for E2 detection with a panel of human volunteers (n = 49) is 39 nM E2 (15 nM when “non-smellers” are excluded). This concentration of E2 is sensitive enough to detect levels of E2 that would be found in dosage forms. This manuscript provides evidence that scent has potential for use in portable yeast biosensors as a read out, particularly for use in technology-limited environments.</jats:p>

Engineering Saccharomyces cerevisiae‐based biosensors for copper detection

“…S. cerevisiae that capitalizes on the orthogonality and specificity of its G‐protein‐coupled receptor (GPCR) mating pathway has been engineered towards an ‘olfactory yeast’ and the resulting yeast could detect an explosive residue mimic of the odorant 2,4‐dinitrotoluene (Radhika et al, 2007). More recently, an olfactory yeast biosensor that detects the hormone estradiol signal based on an odour product of isoamyl acetate was reported (Miller et al, 2020). As inspired by these ‘olfactory’ yeasts, we also attempted to develop odour‐based olfactory outputs for Cu(II) detection.…”

Progress of optical biosensors for analyzing pathogens and organic pollutants in water since 2015

“…Many contaminants or indicators can be measured through yeast-based biosensors, such as pharmaceutical and personal care products (PPCPs), methyl methanesulfonate, formaldehyde, reactive oxidative species inducers, biological oxygen demand (BOD) and doxycycline (Miller et al, 2020a). For example, Saccharomyces cerevisiae (fungus) is an efficient candidate host associated with specific inducible promotors (e.g., CUP1p and copper) for the toxicity of phenol, PPCPs, estradiol, pesticides, and BOD (Gao et al, 2016, Costa et al, 2018, Lobsiger et al, 2019, Miller et al, 2020a, Miller et al, 2020b. Environmental factors, especially temperature, significantly influence the viability of yeast biosensors, that control the yeast activities and affect the stability of the biosensors (Jarque et al, 2016).…”

High-performance Saccharomyces cerevisiae-based biosensor for heavy metal detection

“…cerevisiae that capitalizes on the orthogonality and specificity of its G protein-coupled receptor (GPCR) mating pathway has been engineered toward an "olfactory yeast" and the resulting yeast could detect an explosive residue mimic of the odorant 2,4dinitrotoluene (35). More recently, an olfactory yeast biosensor that detects the hormone estradiol signal based on an odor product of isoamyl acetate was reported (36). As inspired by these "olfactory" yeasts, we also attempted to develop odor-based olfactory outputs for Cu(II) detection.…”